A 3D visual effect may be generated by presenting different images to a viewer's left and right eyes. Each of the left and right eye images represent different perspectives of the same scene or object. The viewer's brain combines and interprets the left and right eye images to perceive a single 3D image having the illusion of depth.
One method of creating a 3D visual effect on a display is to provide spectrally filtered light to the viewer so that the left eye is presented with light in a first set of spectral bands (providing a left eye image) and the right eye is presented with light in a complementary, second set of spectral bands (providing a right eye image). The viewer wears spectral filtration glasses to view the spectrally separated left and right eye images. The glasses have a left eye filter allowing light within the first set of spectral bands to pass through, and blocking substantially all light which is not within the first set of spectral bands. The glasses also have a right eye filter allowing light within the second set of spectral bands to pass through, while blocking substantially all light which is not within the second set of spectral bands. The display may alternate between displaying the left and right eye images so that the left and right eye images are time-multiplexed. FIG. 1A illustrates two complementary sets of red, green and blue (R, G, B) spectral bands which may be used for displaying left and right eye images. FIG. 1A plots intensity as a function of wavelength for light having a spectral composition comprising a first set 11 of spectral bands R1, G1 and B1 (which may be used as the left eye spectral bands), and for light having a spectral composition comprising a second set 13 of spectral bands R2, G2 and B2 (which may be used as the right eye spectral bands).
Spectral filtration has been applied to projection displays. Some examples of projection displays using spectral filtration are described in: United States Patent Application Publication No. 2008/0284982 published 20 Nov. 2008 and entitled SPECTRAL SEPARATION FILTERS FOR 3D STEREOSCOPIC D-CINEMA PRESENTATION and United States Patent Application Publication No. US2008/0278807 published 13 Nov. 2008 and entitled METHOD AND SYSTEM FOR SHAPED GLASSES AND VIEWING 3D GLASSES.
Spectral filtration has also been applied to backlit displays. Some examples of backlit displays using spectral filtration are described in: United States Patent Application Publication No. 2007/0188711 published 16 Aug. 2007 and entitled MULTI-FUNCTIONAL ACTIVE MATRIX LIQUID CRYSTAL DISPLAYS, United States Patent Application Publication No. 2008/0094528 published 24 Apr. 2008 and entitled LED ILLUMINATION FILTERS, and United States Patent Application Publication No. 2009/0085912 published 2 Apr. 2009 and entitled FULL-COLOR ANAGLYPH THREE-DIMENSIONAL DISPLAY.
One type of dual modulation display has a light source modulation layer comprising an array of light sources (e.g. solid state illumination devices such as LEDs) and a display modulation layer comprising an array of pixels (e.g. LCD pixels). The light sources may be driven to spatially modulate the intensity of light directed at the display modulation layer. The display modulation layer pixels may be driven to spatially modulate the amount of light passed through the pixels. Some examples of dual modulation displays are described in: U.S. Pat. No. 6,891,672 issued 10 May 2005 and entitled HIGH DYNAMIC RANGE DISPLAY DEVICES, U.S. Pat. No. 7,403,332 issued 22 Jul. 2008 and entitled HIGH DYNAMIC RANGE DISPLAY DEVICES, and United States Patent Application Publication No. 2008/0180466 published 31 Jul. 2008 and entitled RAPID IMAGE RENDERING ON DUAL-MODULATOR DISPLAYS all of which are hereby incorporated herein by reference for all purposes. There is a general desire to provide alternative methods and systems for displaying 3D images.